H6-type transformerless single-phase inverter for grid-tied photovoltaic system

There has been an increasing interest in transformerless inverter for grid-tied photovoltaic (PV) system because of the benefits of lower cost, smaller volume as well as higher efficiency compared with the ones with transformer. However, one of the technical challenges of the transformerless inverter is the safety issue of leakage current which needs to be addressed carefully. In addition, according to the international regulations, transformerless inverter should be capable of handling a certain amount of reactive power. In this study, a new H6-type transformerless inverter for grid-tied PV system is proposed that can eliminate the threat of leakage current. The proposed topology has also the capability to inject reactive power into the utility grid. Three-level output voltage employing unipolar sinusoidal pulse-width modulation can be achieved with the proposed topology. The proposed topology structure and detail operation principle with reactive power control are investigated. The relationship among the existing topologies and their reactive power control capability are also discussed. The proposed topology is simulated in MATLAB/Simulink software to initially verify the accuracy of theoretical explanations. Finally, a universal prototype rated 1 kW has been built and tested. The experimental results validate the theoretical analysis and simulation results.

[1]  Hurng-Liahng Jou,et al.  Transformer-less three-port grid-connected power converter for distribution power generation system with dual renewable energy sources , 2012 .

[2]  Iván Patrao,et al.  Transformerless topologies for grid-connected single-phase photovoltaic inverters , 2011 .

[3]  Jianhua Wang,et al.  High-Efficiency Single-Phase Transformerless PV H6 Inverter With Hybrid Modulation Method , 2013, IEEE Transactions on Industrial Electronics.

[4]  Tamas Kerekes Analysis and Modeling of Transformerless Photovoltaic Inverter Systems , 2009 .

[5]  Fei Zhou,et al.  Leakage current analysis of a single-phase transformer-less PV inverter connected to the grid , 2008, 2008 IEEE International Conference on Sustainable Energy Technologies.

[6]  Jih-Sheng Lai,et al.  High-Efficiency MOSFET Inverter with H6-Type Configuration for Photovoltaic Nonisolated AC-Module Applications , 2011, IEEE Transactions on Power Electronics.

[7]  Li Zhang,et al.  H6 Transformerless Full-Bridge PV Grid-Tied Inverters , 2014, IEEE Transactions on Power Electronics.

[8]  Jung-Min Kwon,et al.  Single-phase transformerless bi-directional inverter with high efficiency and low leakage current , 2014 .

[9]  Monirul Islam,et al.  High efficiency transformerless MOSFET inverter for grid-tied photovoltaic system , 2014, 2014 IEEE Applied Power Electronics Conference and Exposition - APEC 2014.

[10]  Nasrudin A. Rahim,et al.  Comparison and Analysis of Single-Phase Transformerless Grid-Connected PV Inverters , 2014, IEEE Transactions on Power Electronics.

[11]  Frede Blaabjerg,et al.  Methodology for the optimal design of transformerless grid-connected PV inverters , 2012 .

[12]  Quan Li,et al.  A Review of the Single Phase Photovoltaic Module Integrated Converter Topologies With Three Different DC Link Configurations , 2008, IEEE Transactions on Power Electronics.

[13]  Zheng Zhao High Efficiency Single-stage Grid-tied PV Inverter for Renewable Energy System , 2012 .

[14]  Juan Carlos Balda,et al.  A PV dispersed generator: a power quality analysis within the IEEE 519 , 1998, 8th International Conference on Harmonics and Quality of Power. Proceedings (Cat. No.98EX227).

[15]  Remus Teodorescu,et al.  A New High-Efficiency Single-Phase Transformerless PV Inverter Topology , 2011, IEEE Transactions on Industrial Electronics.

[16]  A. Ahfock,et al.  Direct current offset controller for transformerless single-phase photovoltaic grid-connected inverters , 2010 .

[17]  L. A. Lamont,et al.  PV Technology - Industry update , 2010, IEEE PES General Meeting.

[18]  Peter Zacharias,et al.  Highly Efficient Single-Phase Transformerless Inverters for Grid-Connected Photovoltaic Systems , 2010, IEEE Transactions on Industrial Electronics.

[19]  D. Boroyevich,et al.  Leakage Current Reduction in a Single-Phase Bidirectional AC–DC Full-Bridge Inverter , 2012, IEEE Transactions on Power Electronics.

[20]  David J. Atkinson,et al.  Approach to low-cost prevention of DC injection in transformerless grid connected inverters , 2010 .

[21]  Tsai-Fu Wu,et al.  Combined Unipolar and Bipolar PWM for Current Distortion Improvement During Power Compensation , 2014, IEEE Transactions on Power Electronics.

[22]  Kavya Gundagani,et al.  High Reliability And Efficiency Single-Phase Transformerless Inverter For Grid-Connected Photovoltaic Systems , 2014 .

[23]  Kai Sun,et al.  A Family of Neutral Point Clamped Full-Bridge Topologies for Transformerless Photovoltaic Grid-Tied Inverters , 2013, IEEE Transactions on Power Electronics.

[24]  Giampaolo Buticchi,et al.  Digital Control of Actual Grid-Connected Converters for Ground Leakage Current Reduction in PV Transformerless Systems , 2012, IEEE Transactions on Industrial Informatics.

[25]  Huafeng Xiao,et al.  Optimised full-bridge transformerless photovoltaic grid-connected inverter with low conduction loss and low leakage current , 2014 .

[26]  P. Sanchis,et al.  Transformerless Inverter for Single-Phase Photovoltaic Systems , 2007, IEEE Transactions on Power Electronics.